Unprecedented research has revealed fascinating new details about the Maya civilization—which dominated the region covering what is now southeastern Mexico, Guatemala, Belize, El Salvador and Honduras for more than 2,500 years.

An international team of researchers spearheaded by the non-profit consortium PACUNAM (Foundation for Maya Cultural and Natural Heritage) employed a revolutionary imaging technique known as LiDAR to survey more than 2,000 square kilometers (772 square miles) of tropical forest in northern Guatemala—an area known as the Maya Lowlands—uncovering thousands of ancient structures. The findings will force us to reevaluate several aspects of the mysterious ancient civilization, experts say.

LiDAR makes use of instruments fitted on aircraft that fire pulses of laser light towards the ground 900,000 times per second, enabling the creation of detailed 3D maps that reveal the topography of the land and any ancient man-made features.

Much of the Maya Lowlands—the demographic and political heartland of the Classic Maya culture—are heavily forested, making on-the-ground research and the discovery of new sites very difficult. Fully mapping and characterizing a single settlement can take many years. As a result, our understanding of many aspects of Maya urban civilization, land use and socio-political complexity remains limited.

With LiDAR, however, researchers can essentially "see through" the jungle canopy revealing features—such as ancient structures or roads—that are normally hidden by vegetation. This is possible because a small percentage of the laser pulses—around five percent—are able to penetrate through to the ground. These investigations can be conducted far more quickly than on-the-ground fieldwork (although this is still crucial).

The latest work—part of an ongoing project known as the PACUNAM LiDAR Initiative (PLI)—is the largest LiDAR survey of the Lowland region to date and includes the iconic ruins of the ancient city of Tikal. The results of the survey and analysis of the data collected have been published in the journal Science.

"[The key findings] are the scale and complexity of Maya urbanism and agriculture," Francisco Estrada-Belli, a Maya archaeologist and author of the latest study, told Newsweek. "We were able to appreciate the size and density of Maya cities at a scale that had not been seen before."

Analysis of this data suggested that between 7 and 11 million people lived throughout the Maya Lowlands during the Late Classic Period (650-800 C.E.)—a figure that is broadly in agreement with previous estimates. This ancient population was unevenly distributed across the central lowlands with varying degrees of urbanization.

To sustain such a population for many centuries, intensive agriculture would be required, but to date, evidence of this has been lacking. The LiDAR survey reveals, however, that a great deal of the wetlands throughout the region were heavily modified for agricultural use. In fact, the researchers identified 362 square kilometers (140 square miles) of terraces, or otherwise modified terrain, and another 952 square kilometers of viable farmland.

Furthermore, they found evidence of monumental water management systems, roadways connecting distant cities and smaller populations, and extensive defensive infrastructure. This substantial investment in such infrastructure highlights both the connectivity of the cities and hinterlands, while also indicating a high incidence of conflict in the Maya Lowlands, the study authors say.

According to the researchers, the new data helps to address important debates about Maya civilization in the Lowland region.

For example, some experts have suggested that the Maya Lowlands contained small city-state centers ruled by warring elites. In this view, these settlements were supported by a relatively sparse population practicing rotational farming techniques—where land is cleared for cultivation and left to regenerate—with only a limited use of intensive agriculture.

In contrast, other views suggest that there was a regional network of densely populated, highly-integrated cities that depended on heavy labor both inside and outside the urban centers.

"Even though the latter view has been ascendant in recent years, the absence of regional data has left the debate unresolved," the authors wrote in the study.

The new results, however, provide support for the latter model, they say, while also opening up important new avenues for future field research in the region.

"These results show that many theories on the Maya are about to change and at a fast pace if we continue to acquire LiDAR data and share those data among collaborating scholars in real time," Estrada-Belli said. "So far, we have been able to discover many aspects of Maya civilization we had not appreciated—the size of their cities, the sophistication of their agricultural engineering, as well as the scale of their wars. Many more discoveries will be made if archaeologists have access to LiDAR-generated Big Data."

View of Tikal in the Maya Lowlands from Temple 4 showing the crests of Temples 1-3 and 5 emerging from the jungle.Estrada-Belli

In fact, LiDAR has already produced impressive results in the field of Maya archaeology. Earlier this year, the PLI announced the discovery of an unprecedented network of ancient Maya features in Guatemala, including palaces, elevated highways and thousands of houses, which, much like the finds in the latest research, had been hidden below the jungle for centuries. These important results indicated that the Maya civilization was far more complex and interconnected than previously thought.

For Anabel Ford, a Maya expert at the University of California, Santa Barbara's Department of Anthropology, surveys using LiDAR will enable researchers to understand the mystery of how the Maya lived in harmony with their their tropical forest environment.

"My work has demonstrated that the ancient Maya were able to work with nature," she said in comments provided to Newsweek. "They were forest gardeners using observational skills developed over centuries, scheduling their annual planting and reaping cycle, their clearing and growing cycle, and their perennial management cycle, to work with the forest."

"That is why the dominant plants that blanket the landscape are all useful for fruit, wood, roofs, construction, products, oils, medicine, incense, poison," she said. "In short, everything for daily needs can be found within the immediate garden spaces or a short walk away. I hope that the results of LiDAR [surveys] will help reframe the question of the Maya and their forest."

While Ford praises the benefits of LiDAR, she stresses that field work is still a vital to validate features on the ground.

"For archaeology, LiDAR presents an extremely accurate view of the geography and topography of the landscape," she said. "This is for any landscape, but in the case of forests, and the Maya forest in particular, it is like a magic wand —an expensive one!"

"However at the site scale, the features that you may identify as architecture—a small house, a group of structures—cannot be certain without field validation. The big stuff is clear, but the subtle uses of the landscape by the ancient agricultural Maya Civilization requires verification."

The Maya civilization peaked around 1,200 years ago before experiencing a decline, surviving right up until 1697 when the last city fell to Spanish conquistadors. The Maya were notable for creating the only fully developed writing system in pre-Columbian America, as well as their sophistication in architecture, art, mathematics, and astronomy.

While the Spanish conquest of Mesoamerica stripped away most of the defining features of independent Maya civilization, millions of Maya people still inhabit the Yucatán peninsula and their culture persists to this day.

This article has been updated to include additional comments from Francisco Estrada-Belli and Anabel Ford.